Giant optical transmission through a metallic nano-slit achieved by the optimization of the groove periodicity and other parameters

The extraordinary optical transmission of light through a metallic nano-slit surrounded by groove corrugations can further be increased by optimizing the geometric parameters including the period of the corrugations, the period which has been set to be equal to the surface-plasmon wavelength in most of the previous works. By a global optimization, we are able to enhance the transmission efficiency of light through a silver nano-slit of 25 nm-wide as high as 18500 percent when the slit is surrounded by only 6 pairs of grooves.